Improvement in steam-engine valves



idniir %tair5 @anni Ctifitt Letters Patent No. 113,810, dated April 18,1871.

IMPROVEMENT IN STEAM-ENGINE VALVES.

The Schedule referred to in these Letters Patent and making paxt of thesame.

To all 4"persons to whom these presents may come Be it known that 1,NATHAN PAGE STEVENS, of Hopkinton, of the county of Merrimac, of theState of New Hampshire, have invented a new and useful Improvement inSteam -Engine Valves and their Chests; and do hereby declare the same tobe fully described in the following specification and represented in theaccompanying drawing, of whichlFigures 1 and 2'are vertical sections,taken in planes at right angles to leach other, of my improved valve andits chest as applied to the cylinder of an engine.

Figure 3 is an under-side view of the valve.

Figure 4 is a top view ofthe valve-seat or the baseplates of thevalve-chest.

The valve-chest A is made ,open at one or both opposite ends in mannerso that the valve B may be introduced into and drawn out ofthe chestthrough the open end, the said valve being hat on its upper and lowerfaces, and the two being parallel.

The-chest A is surmounted with a hollow dome, C, to open into it and toreceive the steam through an induct, D, leading into such dome.

Encircling the hase ot' the dome is a groove, a, made lin the upperplate or top of the chest, such groove being arranged in manner asrepresented in figs. l and 2.

Within this groove is an annulus or ring-packing,

when necessary, without requiring any part or fixture c, of metal orother suitable material.

Furthermore, through the base-plate or valve-seat d of the chest are twoparts, ee, to lead to the opposite ends of the cylinders.

Besides4 these parts there are two other openings, ff, .madedown throughsuch base-plate and into a common Aexhaust-passage, g, the dispositionor arrangement ofsuch openings f f relatively to the parts e e beingshown in iig. 4. l

'lhe 'valve B is a block of metal having its opposite upper and lowersurfaces parallel.

The valvel has formed in it a receiving-chamber or space, h, and anencompassing channel or groove i, suclr chamber and grooveopeningthroughthe base or lower face of the valve.

The chamber also has an opening, la, leading out of its top, all beingarranged in manner as shown in the drawing,the valve-stem t beingpivoted, or hinged, or otherwise properly fixed to the valve.

With the valve and chest so constructedV steam, after entering the domeC, passes down through the valve-opening k into the receiving-chamberIl..

During the reciprocating movements of thevalve within its chest suchchamber h will belmovedl alternately over the parts e e, each of whichwill be closedl by the valve while the other is open to the chamber.

Those portions of the valve which are to operate to close and open theparts ee are shown at m m.

While one of such parts m covers one part, the other part will'beluncovered and in free communication with the passage or chamber i, thesame being so as to cause the exhaust steam to pass into such channel,and from thence through the openings f j, and into the commonescape-passage y.

I would remark that only one opening, f, into the exhaust-passage g isrequisite, although it is better to have two, because they relieve thevalve ot' ,the steam quicker and more evenly than one part only would.

It will be observed that in the said valve and chest the induction ofthe steam is through the valve, whereas in most if not all other slidelvalves'the eduction takes place through them. V

Some-of the advantages incident to my construction of valve and chestare as follows:

First, the valve is substantially a balanced valve.

Second, in case of leakage of steam from beneath the valve and its seatsuch waste of steam, instead of blowing out the side of the valve-chest,will pass directly into the channel fi, from' whence it will ilow intothe exhaust-passage. v

Third, the valve can be removed from the chest,

of the chest to be previously removed from` the rest.

Fourth, no stuffing-box to the valve-stem becomes necessary.

Fifth, the packing-ring over the valve will, by, the steam that entersthe groove for receiving such ring, be forced down upon the valve so asto produce a steamtight joint around the valve induction opening.

If desirable, there may be a passage leading into the packing-ringgroove in order to render certain the ent-rance oi' the -steam therein.

i make no claim to a packing-ring and groove in the abstract, or asordinarily applied and used.

I claim as my invention the following, viz:

'lhe valve as made, with the receiving-chamber h open at top and bottom,and with the encompassing exhaust-channel i, iu combination with themain parts e e and the lateral exhaust-passage or passages f, allarranged in or with respect to the chest in manner and to operate asspecified.

NATHAN PAGE STEVENS.

XVitnesses:

R. H. EDDY, J. 1t. Snow.

